<template>
  <div class="spec-preview">
    <img ref="img1"  v-lazy="skuInfo.skuDefaultImg" />
    <div class="event" @mousemove="move"></div>
    <!-- 右侧的大图  这个大图和左边的图片其实是一个，只不过是放大2倍 -->
    <div class="big">
      <img   ref="img2"
           v-lazy="skuInfo.skuDefaultImg" 
            :style="{left: -2 * left + 'px', top: -2 * top + 'px'}" />
    </div>
    <!-- 遮罩层 -->
    <div class="mask" :style="{left:left + 'px',top:top + 'px'}"></div>
  </div>
</template>

<script>
import {mapGetters} from 'vuex'
  export default {
    name: "Zoom",
    data(){
      return {
         left:0,
         top:0
      }
    },
    computed:{
      ...mapGetters('detail',['skuInfo'])
    },
    methods:{
        //1.实现放大镜的效果
       move(event){
          //console.log(event);
          let x = event.offsetX - 100;
          if(x<0){
              x = 0
          }
          if(x>200) x = 200;
           this.left= x;
          let y = event.offsetY - 100;
          if(y<0) {
            y = 0;
          }
          if(y>200) y = 200;
          this.top = y
       }
    },
     mounted(){
       // 1. 实现单击小图显示大图效果
         this.$bus.$on('get-image',(imgUrl)=>{
              this.$nextTick(()=>{
                   if (this.$refs.img1) {
                    this.$refs.img1.src = imgUrl;
                    this.$refs.img2.src = imgUrl;
                  }
              })
         })
     },
     beforeDestroy(){
        this.$bus.$off('get-image') //销毁自定义事件
     }

  }
</script>

<style lang="less" scoped>
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>